The invention relates to an arrangement with a particle beam probe for voltage measurement at a test subject which is spatially separated from a surface by an insulating solid state substance.
In the past, electron beam mensuration technology has proven itself as a practical method for contact-free measurement of voltage progressions in integrated circuits (H. P. Feuerbaum, "VLSI Testing Using the Electron Probe", Scanning Electron Microscopy/1979/I, 285-296, incorporated herein by reference). The measuring principle disclosed by H. P. Feuerbaum has been applied to measuring points which are situated at the circuit surface. Given the increasing degree of integration of the circuits, however, multi-layer wirings are more and more frequently employed so that there will be a need in the future to identify the potential of tracks buried in the semiconductor chip.
According to the prior art, there is no simple and efficient measuring method for quantitative voltage measurement at buried tracks without additional processing or procedure steps at the circuit. It has been proposed by J. Frosien to bore through to the hidden tracks and to identify the potential of these tracks through the bores. Such a method, however, requires a considerable additional processing cost.
L. Kotorman, Scanning Electron Microscoph/1980/IV, pp. 77-84, incorporated herein by reference, has proposed that the potential of the buried track be capacitively identified at the surface of the insulator under which the track is buried via the electrical polarization of the insulator. In practice, such a method will probably supply only imprecise measurement results since the polarized surface of the insulator represents an extremely low-load voltage source which is determined only by the capacitance of the area on the surface of said insulator irradiated by the particle beam probe. Secondly, the voltage distribution at the surface of the insulator does not correspond to the voltage distribution of the track since this voltage distribution at the surface of the insulator is generated by an inhomogeneous electrical field.